Prior to the present invention, various controls have been provided to meter fuel to an injection pump which delivers pressure waves of fuel to the separate cylinders of an internal combustion engine such as for powering a vehicle. In co-pending patent application Ser. No. 393,183 filed Aug. 14, 1989, in the names of M. A. Mitchell and D. P. Sczomak and hereby incorporated by reference, a metering valve is disclosed with a variable fuel restriction mechanically controlled by an engine governor that supplies varying amounts of fuel per unit time in accordance with engine speed so that fuel flow to the pump and cylinders is determined by the particular position of the metering valve and not by the rotor and rotor sleeve communication ports or windows in the injection pump. Such construction requires mechanical linkage between the governor and metering valve that is unable to cut off and tailor amounts of fuel to each separate cylinder in accordance with their varying requirements for optimized engine operation.
To provide improved control over the fuel supplied to each cylinder and, as disclosed in U.S. Pat. No. 4,539,956 issued Sept. 10, 1985 in the names of J. F. Hengel, D. J. Armstrong, F. Ament, M. B. Center and J. E. Ausen and hereby incorporated by reference, a solenoid valve has been utilized in parallel and in series with a governor controlled metering valve. While that construction provided for improved cylinder to cylinder fuel control, a governor controlled metering valve was still utilized and the solenoid arrangement was additive to provide the control at the start of the fuel flow into the fuel delivery ports provided in the distributor pump of this unit.
The present invention is of the general category of that of U.S. Pat. No. 4,539,956 but provides a straightforward and simplified construction and entirely eliminates the governor controlled metering valve system. The present invention utilizes an electronically controlled inlet metering solenoid for improving the cylinder to cylinder injection of pressure waves of fuel into the various cylinders of the engine which are metered in varying widths in accordance with requirements so that each cylinder will produce a predetermined torque such as an equalized torque for each cylinder.
It is a feature, object and advantage of this invention to provide a new and improved electronic fuel control which rapidly cuts off the flow of fuel that is being delivered to the distributor or delivery pump while the fuel ports to the pumping elements are in registry to control the quantity of fuel that will be delivered to the injector nozzles and cylinders. With variable end of the fluid flow through the rotor sleeve communicating with the port areas there is precise control over the amounts of fuel delivered to each of the cylinders so that the torque output of the cylinders can be equalized or adjusted to provide the torque output desired. When a sufficient quantity of fuel for each pumping event is delivered to the delivery pump, the solenoid valve quickly closes under the action of an associated closure spring to provide a precise cutoff of the pressure fuel input to the pump and delivery valve with the cutoff being adjusted to occur when the ports are in registry. The effective metering and pulse width control is accomplished in the inlet port area and with the cutoff providing the precisioned fuel metering control. Accordingly, with the present invention, there is improved cylinder to cylinder fuel control such as for improved idle, soot control, smooth engine operation and engine efficiency.
These and other features, objects and advantages of this invention will be more apparent from the following detailed description and drawings in which: